1. Field of the Invention
The present invention relates generally to gear systems. More specifically, the invention is a wedge clutch assembly for insertion in power hand tools and drilling apparatus to prevent damage to a gear drive system upon excessive stress.
2. Description of the Related Art
The related art of interest describes various clutch assemblies, but none of the cited references discloses the present invention. There is a need to provide a mechanism to avoid gear failure in power hand tools and even in well drilling apparatus. The relevant art will be discussed in the order of perceived relevance to the present invention.
U.S. Patent Application Publication No. US 2002/0062967 published on May 30, 2002, for Bernd Ziegler describes an electrical hand-held power tool with an electromagnetic safety clutch provided between a pinion shaft and a rotor shaft. The pinion shaft is formed as a hollow shaft provided in its interior with an inner bearing which rotatably supports the pinion shaft. The rotor shaft has its end received in the interior of the pinion shaft and supported against the inner bearing. The safety clutch is distinguishable for requiring an electromagnetic means.
U.S. Pat. No. 3,625,292 issued on Dec. 7, 1971, to Michael T. Lay describes an insulated slip clutch for a power cutting tool such as a lawn edger and grass trimmer. A slip clutch made of Bellville washer springs is held in place by a retaining nut which allows the D-shaped end of the drive shaft to continue to rotate, but to immobilize the drive pinion and any cutting motion. The slip clutch is housed between the cutting blade and a plastic casing in two insulating cups and a liner with a D-shaped hole. The clutch assembly is deemed distinguishable for requiring the driving shaft end to have a flattened D-shaped cross-section, Bellville washer springs and a two-cup insulating casing.
U.S. Pat. No. 4,606,443 issued on Aug. 19, 1986, to Misao Kimura describes a planetary drive with an overload clutch release means for a telescopic antenna comprises an intermediate gear which meshes with a gear portion provided on an inner surface of a driven rotary member and a clutch gear which meshes with the intermediate gear to comprise the planetary gears. The clutch assembly is distinguishable for requiring a planetary drive with an intermediate gear for raising and lowering a telescopic antenna.
U.S. Pat. No. 3,752,278 issued on Aug. 14, 1973, to Ronald F. States describes an improved power operated wrench or screwdriver having two dog clutches in series for the transmission of the drive in which one is a torque sensitive dog clutch having ramped interengaging driving surfaces adapted to be induced to become displaced against the action of a spring when the torque applied by the tool exceeds a predetermined value. The other dog clutch is a non-torque sensitive clutch which is adapted to become disengaged by displacement of the torque sensitive clutch. The dog clutches are distinguishable for requiring two having different torque sensitivities.
U.S. Pat. No. 4,053,980 issued on Oct. 18, 1977, to Arthur G. Poehlman describes a chain saw including an overtorque releasing clutch mechanism comprising a drive member driven by the drive shaft and a driven member for rotating the chain sprocket. One of the members is axially movable relative to the other between an engaged or driving position and a released position wherein they are disengaged from each other. The drive and driven members have intermeshing clutch teeth which coact to produce an axial force in a direction tending to separate the members which are releasably held by a resilient member. The clutch mechanism is distinguishable for requiring intermeshing clutch teeth.
U.S. Pat. No. 4,066,136 issued on Jan. 3, 1978, to Karl Wanner et al. describes a torque and impulse transmitting portable hammer drill having a safety overload clutch mechanism inserted in series between the rotary shaft of the motor and the tool to terminate the transmission of torque from the rotary shaft to the tool when resistance to rotation exceeds a predetermined value. An intermediate gear with smaller teeth is positioned between the crank gear and the coupling gear. The clutch is distinguishable for requiring a third gear.
U.S. Pat. No. 4,809,572 issued on Mar. 7, 1989, to Katsuhiko Sasaki describes a power driven screwdriver having a claw clutch comprising a fixed clutch member with teeth on the end of a main gear on a support shaft. The spindle has a movable clutch member with teeth and an engaging ball in an inclined groove. A spring is located between the movable clutch member and the fixed clutch member. The claw clutch is distinguishable for requiring engaging teeth and an engaging ball.
U.S. Pat. No. 4,883,130 issued on Nov. 28, 1989, to Paul H. Dixon describes a rotating dual speed transmission for a screw fastener driving tool of an automatic assembly machine which acts in conjunction with two torque-responsive clutches to tighten a threaded fastener such as a screw or a nut during rotation of the spindle. A first torque-responsive clutch automatically switches the drive from a fast speed to a slow speed when torque of a predetermined magnitude is imposed on the fastener, and a second torque-responsive clutch automatically interrupts the drive to the fastener when torque of a higher predetermined magnitude is imposed on the fastener. The first lower clutch has lugs which lock with the lower cam segments supported with a coil spring around the spindle. The upper clutch has lugs which lock with the jaw members of the lower clutch. The clutches are distinguishable for requiring locking elements such as lugs and cam segments.
U.S. Pat. No. 4,967,888 issued on Nov. 6, 1990, to Wolfgang Lippacher et al. describes a safety clutch for a motor-driven hammer drill which breaks the rotational drive train when a working tool becomes seized in a receiving material. A pair of coupling balls upon seizure leave their recesses in the power take-off spindle housing to permit the drive to continue to rotate. However, the motor must be stopped and restarted. The safety clutch assembly is distinguishable for requiring coupling balls.
U.S. Pat. No. 5,060,772 issued on Oct. 29, 1991, to Heinz-Gerhard Anders et al. describes a pneumatic power-operated screw driving tool which includes a switching clutch to transfer the torque from the drive shaft to an output shaft when the tool seizes. The driver has a first clutch having clutch coupling jaws at its end which engages the coupling jaws of the second clutch. The clutch system is distinguishable for requiring two engaging clutches with jaws.
U.S. Pat. No. 5,094,133 issued on Mar. 10, 1992, to Wolfgang Schreiber describes a power-operated screwdriver with a switch-off means for screw-in depth and screw-in torque having three clutch elements. A first clutch element arranged between the drive and the tool drive shaft, and transferrable by axial displacement of the tool drive shaft from a rest position to a working position. A second clutch element connected to the tool drive shaft. A third clutch element arranged between the first and second clutch elements forms an entrainment clutch with the first clutch element and forms a release clutch with the second clutch element. The clutch system is distinguishable for requiring three connecting clutches.
U.S. Pat. No. 5,134,909 issued on Aug. 4, 1992, to Katsuhiko Sasaki describes a power driven screwdriver including a driving or frictional clutch mechanism interposed between the drive motor and the spindle. A claw clutch mechanism is interposed between the spindle and a second driving member which is separated from a first driving member. The clutch system is distinguishable for requiring a frictional clutch and a claw clutch.
U.S. Pat. No. 5,138,916 issued on Aug. 18, 1992, to Yuichi Sato et al. describes a power operated screwdriver having two clutches, a compression spring between a support shaft and an intermediate clutch disc and urges the clutch disc toward the main spindle to disengage the first clutch. The clutch system is distinguishable for requiring two clutches.
U.S. Pat. No. 5,350,026 issued on Sep. 27, 1994, to Heule Markus et al. describes an electric power-driven screw-driver having a single friction coupling consisting of first and second coupling elements that undoes the drive connection between a driving electric motor and the tool output shaft.
U.S. Pat. No. 5,372,206 issued on Dec. 13, 1994, to Katsuhiko Sasaki et al. describes a tightening tool including a drive member rotatably driven by a motor. An intermediate member is interposed between the drive member and a spindle, and rotatable with the drive member. A claw clutch is formed between the spindle and the drive member. The clutch system is distinguishable for requiring a claw clutch.
U.S. Pat. No. 5,538,089 issued on Jul. 23, 1996, to Christopher P. Sanford describes a power tool clutch assembly having a first spindle configured to rotate in a gear case. A drive clutch element is fixed to the first spindle. A second spindle rotates independently of the first spindle. An output clutch element is fixed to the second spindle. A compression spring is provided between the intermediate and output clutch elements. The clutch housing and clutch components can be removed from a power tool gear casing for easy service. The clutch assembly is distinguishable for requiring two clutches.
U.S. Pat. No. 5,566,458 issued on Oct. 22, 1996, to Thomas R. Bednar describes two embodiments of a clutch mechanism for reciprocating saws having a wobble plate drive member including a spindle reciprocally supported by the housing, and a clutch drivingly connecting the motor to the shaft and providing slippage between the motor and the shaft if there is binding of the spindle. The clutch mechanisms are distinguishable for requiring structurally different elements.
U.S. Pat. No. 5,573,091 issued on Nov. 12, 1996, to Michael Hung describes an electrically powered or manually driven clutch and brake assembly for an electric winch cooperating with a transmission assembly. The clutch mechanism is provided with a thrust bearing on a clutch shaft, and a large clutch gear is inserted thereon. A lining plate is attached to a clutch plate of the large gear, and a pinion gear is attached tightly to the lining plate. Another thrust bearing is placed behind the pinion gear and a compression spring is inserted on the clutch shaft. The large gear and the pinion gear are pushed tightly together or loosened as a function of the resiliency of the spring. A clutch hand wheel can be provided for manual operation. The clutch mechanism is distinguishable for requiring a large clutch gear, a lining plate and two thrust bearings.
U.S. Pat. No. 5,622,230 issued on Apr. 22, 1997, to David A. Giardino et al. describes a rotary impact wrench clutch comprising a two-part, readily assembled and disassembled pin cage-coupler. One part is a cylindrical, longitudinally grooved cage contains a clutch mechanism and capped at one end by a lobed end plate coupler. The clutch device is distinguishable for requiring a pin-cage coupler.
U.S. Pat. No. 5,778,989 issued on Jul. 14, 1998, to Anton Neumaier describes a manually operable screw driving tool having a drive pinion axially fixed with a housing. A spindle in the housing is axially displaceable relative to the drive pinion against the force of a first spring. A clutch element is located in a passageway in a collar on the drive pinion, and is radially displaceable by an actuating member for engaging the spindle to the drive pinion. In the engaged position the clutch element sits against a stop surface in the spindle. The actuation member is axially displaceable by stops located on the spindle, and can be axially fixed to the drive pinion by a retaining element and a snap-element. The clutch element is distinguishable for requiring an actuation member axially displaceable by stops on the spindle.
U.S. Pat. No. 6,283,226 B1 issued on Sep. 4, 2001, to Kenneth Chen describes a clutch-buffer assembly for a power wrench comprising a driven wheel having an outwardly positioning tube disposed at a power-input end. A retaining spring, a retaining disc, a driven gear, an anchor ring, and a reversible motor are collared onto the positioning tube sequentially. The retaining disc is limited to move back and forth along the positioning tube without rotation. A pair of protruding teeth and reception cavities in respective contact faces of the retaining disc and the driven gear, and the reversible motor is used to drive the driven gear. When the driven wheel rotates at a higher speed, the retaining disc can be detached from the driven gear for control of the power consumption to lessen the imposed load in order not to blow a fuse. The clutch-buffer assembly is distinguishable for requiring a pair of protruding teeth and reception cavities in the respective contact faces of the retaining disc and the driven gear.
U.S. Pat. No. 6,439,091 B1 issued on Aug. 27, 2002, to John E. Dibbern et al. describes a clutch mechanism for a power tool having a hole and first and second clamps connected to the arbor to clamp the blade. One of the cutting tool and at least one of the first and second clamps and arbor have a first drive surface for contacting a second drive surface on the other of the cutting tool, and at least one of the first and second clamps and arbor. The second drive surface is movable between a first position and a second position bypassing the first drive surface. The second drive surface is resiliently connected to the other of the cutting tool and at least one of the first and second clamps and arbor. At least one metal strip connects the second drive surface to the other of the blade and at least one of the first and second clamps and arbor. The clutch mechanism is distinguishable for requiring two clamps for the blade and first and second drive surfaces.
German Patent Application No. DE 38 07 308 A1 published on Sep. 14, 1989, for Wilhelm Geis et al. describes a radially acting safety friction clutch positioned inside a component of a power tool with an axial mode of action to obtain a shorter and more compact tool. The clutch has compression or cup springs. The clutch is distinguishable for requiring a radially acting safety friction clutch assembly.
German Patent Application No. DE 41 01 705 A1 published on Mar. 26, 1992, for Rainer Warnicki et al. describes a positive, frictionless clutch for a hedge trimmer which has a locking ring to disengage the main gear from a driven bushing by moving two drive rollers into a clear space. The clutch assembly comprises a main drive gear, the driven bushing and a locking ring mounted co-axially on a fixed central shaft. One end of the drive bushing has eccentrics which drive the trimmer blades. Roller located in apertures of the driven bushing transmit the drive through ledges on the inside diameter of the main drive gear. When the trimmer handlegrips are released a stop pin enters a hole in the flange of the locking ring and prevents rotation. The main drive gear and the driven bushing continue rotating, causing the rollers to enter a clear space between the two members and immediately disengaging the drive. A preloading coil spring connects the locking ring to the driven bushing, and together with friction brings the trimmer blades to rest. The clutch assembly is distinguishable for requiring an eccentric drive bushing containing two rollers.
France Patent Application No. 2 799 113 published on Apr. 6, 2001, for Yves Bonin describes a jointed dental hand drill as a continuously rotating instrument having a torque limiter in the form of a spring-loaded sliding gear clutch on the primary drive shaft and a fixed gear on the secondary drive shaft. In the event of a set torque being exceeded, the sliding gear moves along the primary shaft against the pressure of the spring and disengages the transmission. The two gears have asymmetrical teeth to give different torque levels according to the direction of motion. The dental drill clutch system is distinguishable for requiring asymmetrical gear teeth on two gears.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a wedge clutch assembly solving the aforementioned problems is desired.